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Circadin (Melatonin)

  • Used to treat insomnia
  • Active ingredient: melatonin
  • Take one to two hours before bedtime
  • Not suitable for use in children
  • Not to be used while pregnant or breastfeeding

About Circadin

The active substance of Circadin, melatonin, belongs to a natural group of hormones produced by the body.

Circadin is used on its own for the short-term treatment of primary insomnia (persistent difficulty in
getting to sleep or staying asleep, or poor quality of sleep) in patients aged 55 years and older. ‘Primary’ means that the insomnia does not have any identified cause, including any medical, mental
or environmental cause.

How to take Circadin

Always take this medicine exactly as your doctor or pharmacist has told you.


The recommended dose is:

  • Adults: one Circadin tablet (2 mg) once daily. This dosage may be continued for up to 13 weeks.

Do not give this medicine to children between the ages of 0 to 18 years.

Instructions for use:

Take the tablet one to two hours before bedtime, after you have eaten. The tablets should be swallowed whole without chewing. Circadin tablets should not be crushed or cut in half.


Do not drink alcohol before, during or after taking Circadin, because it reduces the effectiveness of Circadin.

Circadin can cause drowsiness. If you are affected, you should not drive or operate machinery. If you suffer from continued drowsiness, then you should consult your doctor.

If you take more or less Circadin than you should

If you have accidentally taken too much of your medicine, contact your doctor or pharmacist as soon
as possible.

If you forget to take your tablet, take another as soon as you remember, before going to sleep, or wait until it is time to take your next dose, then go on as before. Do not take a double dose to make up for a forgotten dose.

When not to use Circadin

Circadin is not suitable for everyone. Do not use Circadin if you are allergic to melatonin or any other ingredient in this medicine (see section 'What Circadin contains’).

When should this medicine be used with caution?

Talk to your doctor or pharmacist before taking Circadin if:

  • You have liver or kidney problems. You should speak to your doctor before taking Circadin as its use is not recommended.
  • You have an intolerance to some sugars.
  • You suffer from an autoimmune disease. You should speak to your doctor before taking Circadin as its use is not recommended.
  • Smoking may make Circadin less effective, because the components of tobacco smoke can increase the breakdown of melatonin by the liver.

Pregnancy and breastfeeding

Do not take Circadin if you are pregnant, think you may be pregnant, trying to become pregnant or
breastfeeding. Ask your doctor or pharmacist for advice before taking this medicine.

Other medicines and Circadin

Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines. These medicines include:

  • Fluvoxamine (used for the treatment of depression and obsessive-compulsive disorder).
  • Psoralens (used in the treatment of skin disorders such as psoriasis).
  • Cimetidine (used in the treatment of stomach problems such as ulcers).
  • Quinolones and rifampicin (used in the treatment of bacterial infections).
  • Oestrogens (used in contraceptives or hormone replacement therapy).
  • Carbamazepine (used in the treatment of epilepsy).
  • Adrenergic agonists/antagonists (such as certain types of medicines used to control blood
  • pressure by constricting blood vessels, nasal decongestants, blood pressure-lowering medicines).
  • Opiate agonists/antagonists (such as medicinal products used in the treatment of drug addiction).
  • Prostaglandin inhibitors (such as nonsteroidal anti-inflammatory medicines).
  • Antidepressants.
  • Tryptophan.
  • Alcohol.
  • Benzodiazepines and non-benzodiazepine hypnotics (medicines used to induce sleep such as
  • zaleplon, zolpidem and zopiclone).
  • Thioridazine (for the treatment of schizophrenia).
  • Imipramine (for the treatment of depression).

For more information, see the package leaflet. Your doctor will also have a list of medicines that you should avoid mixing Circadin with.

Side effects

Like all medicines, this medicine can cause side effects, although not everybody gets them. Side effects that are known to be associated with this medicine include:

Uncommon (may affect up to 1 in 100 people)

  • Irritability.
  • Nervousness.
  • Restlessness.
  • Insomnia, abnormal dreams, nightmares.
  • Anxiety.
  • Headache/ migraine.
  • Lethargy (tiredness, lack of energy).
  • Dizziness.
  • Tiredness.
  • High blood pressure.
  • Nausea, upper abdominal pain, indigestion.
  • Mouth ulceration, dry mouth.
  • Changes in the composition of your blood which could cause yellowing of the skin or
  • eyes.
  • Inflammation of the skin.
  • Night sweats.
  • Itching, rash, dry skin.
  • Pain or discomfort in the limbs.
  • Menopausal symptoms.
  • Feeling of weakness.
  • Excretion of glucose in the urine, excess proteins in the urine.
  • Abnormal liver function.
  • Weight gain.

For a list of less common side effects, please see the package leaflet. Consult a doctor or pharmacist if you experience any side effects. If you experience any serious side effects (see the package leaflet), stop taking the medicine and contact your doctor immediately.

What Circadin contains

The active substance is melatonin. Each prolonged-release tablet contains 2 mg melatonin.

The other ingredients (excipients) are: ammonio methacrylate copolymer type B, calcium hydrogen
phosphate dihydrate, lactose monohydrate, colloidal silicon dioxide anhydrous, talc and magnesium

The manufacturers of Circadin are:

Temmler Pharma GmbH & Co. KG Temmlerstrasse 2
35039 Marburg

Iberfar - Indústria Farmacêutica S.A. Rua Consiglieri Pedroso, n.o 121-123 - Queluz de Baixo
Barcarena, 2734-501

Rovi Pharma Industrial Services, S.A. Vía Complutense, 140
Alcalá de Henares
Madrid, 28805

Package leaflet

Read the package leaflet before use. You can download the official package leaflet of Circadin here.

Patient Leaflet(s)

Reviewed by:

Dr Arco Verhoog, Pharmacist Registrationnumber: BIG: 19065378617 Last checked: 09-02-2024 | Still valid

Affiliated doctors

You know perfectly well what's good and what isn't good for you. Nevertheless, making the right choice can be difficult. We are Dokteronline. We believe in self-management when it comes to your health.

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MD General practitioner / emergency medicine

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